We propose to conduct epidemiologic research concerning the physical and psychological dimensions of temporomandibular disorders (TMD). The research will involve four coordinated tasks, each relying on appropriate cases and controls identified among the enrollees of Group Health Cooperative of Puget Sound (GHC), a large Health Maintenance Organization. The tasks are: 1) establish an epidemiologic database for use in Tasks 2-4 and in future studies. The database will include information on representative samples of treated TMD cases, untreated TMD cases, and persons without TMD; 2) develop diagnostic criteria for TMD syndromes and evaluate these criteria by comparing patterns of TMD signs and symptoms in TMD cases of various types and in the general population; 3) describe the clinical course of TMD and identify factors that are associated with outcome; and 4) conduct exploratory analyses to identify factors that may increase the risk of developing TMD. These tasks will be accomplished by conducting standardized dentists' evaluations of persons referred for treatment of TMD, and by screening a probability sample of GHC enrollees to identify control subjects and untreated "community cases" who have TMD syndromes, but have not been referred for treatment. Data on TMD signs and symptoms and possible TMD risk factors will be collected for treated TMD "clinic cases," community cases and controls through interview and examination procedures conducted by trained dental hygienist examiners. The examination-interview will be repeated one year later for both clinic and community cases to assess outcome of TMD signs and symptoms. GHC medical records data on cases and controls will also be collected. A variety of data analytic techniques will be employed in the epidemiologic description of TMD signs, symptoms and syndromes. Exploratory hypotheses will be evaluated regarding the roles of joint, occlusion and muscle pathologic processes in initiating and maintaining TMD, as well as the relationships of TMD signs and symptoms to psychophysiologic stress, psychosocial functioning (illness and pain behaviors) and affective disturbance (anxiety and depression). This research should contribute to: establishment of reliable and valid diagnostic criteria for TMD; the more rational selection of treatment strategies; and the development of more refined hypotheses for future studies of prevention and treatment.